That’s Shiitake, with two “i’s” and some “D”

Here’s some food for thought: Vitamin D was never intended to be a dietary vitamin.

Vitamin D is produced in the skin from precursors that are activated by the sun’s UVB rays, and travels throughout the body in a hormone-like fashion, doing its thing to help us replenish our bones with calcium and phosphorous after they are temporarily raided to maintain steady blood calcium levels. If we spent more of our lives outdoors, in southern latitudes, sans sunscreen like our ancestors did, we wouldn’t need any Vitamin D in our diets to stay healthy.

Need more proof? Humans have survived for millennia despite the fact that there are VERY few foods that are natural sources of Vitamin D. (Milk and dairy products in the US are fortified by law in order to help prevent rickets, or poor bone mineralization that leads to bowed legs in children and soft, easily broken bones in adults). The only foods that naturally contain Vitamin D in any quantity that matters are fatty fish, liver and sun-dried shiitake mushrooms. (Think its a coincidence that Scandanavian people, living at such northern latitudes, eat so much fatty fish? Among the various types, herring, salmon, mackerel and sardines are best, in that order.) Most of the vitamin D that shows up in an American’s bloodstream comes from sunlight, fortified dairy products, and dietary supplements.

Unfortunately for many of us, we’re not getting enough vitamin D from the sun or from our diets to get our blood levels high enough to benefit from all of Vitamin D’s health-promoting functions. This is especially true for people who live North of 35-degrees latitude, who spend most of their time indoors, who only go out in the sun wearing sunscreen, who don’t drink 8-10 glasses of fortified milk per day, who are older than 50 or who have darker skin. (Like I said, many of us.) Researchers have discovered many other functions for Vitamin D in the body besides calcium absorption and bone mineralization, including protection against colon, breast, ovarian and prostate cancers, protection against autoimmune diseases, protection against hypertension and promoting a better-functioning immune system. The blood levels we need to maintain in order to get the benefit of these functions is higher than previously thought.

In fact, those of us in the ‘biz are expecting the recommended daily value of Vitamin D to be increased from its current level of 5mcg (or 200 IU) for children and adults and 10mcg (400 IU) for adults over 50 in the near future. And when I say increased, we’re not expecting a mere incremental increase. We’re expecting it to go up 4-5x from the current amount, to about 20-25mcg or 800-1,000 IU. How’s that for an insider tip? Stay tuned to see how it all turns out, but if I’m right, then remember that you heard it here first.

So in the spirit of being ahead of the trend, I thought we could talk about one of the few foods that does contain Vitamin D naturally: Sun-dried Shiitake mushrooms. (Of course, most people are still likely to require a mixture of supplements, summer sunshine and fortified foods to meet their full needs, but it still doesn’t hurt to take advantage of a natural–and vegetarian–source when we have one.)

The low-down on Shiitakes

Shiitakes are native to Asia, where they have been used in Chinese medicine and cuisine for ages. These days, you can find them year-round in most supermarkets, though they’re still quite pricey. (My supermarket sells fresh ones for $9.99/lb). The sun-dried version is both more economical AND high in Vitamin D. If you have a local Asian market in your area, you’ll find “large” bags of dried shiitake mushrooms for $5-$10, and once you rehydrate them in warm water, you can cook with them as you would fresh mushrooms. The sun-drying has the same effect on shiitakes as it has in our skin: it transforms inactive vitamin precursors into active vitamin D. So you can’t expect to get any vitamin D from fresh shiitakes, though the they are still very healthful (as a good source of fiber, iron and Vitamin C) and delicious in their own right.

Like other mushrooms, shiitakes are low in carbohydrates and calories. 1 cup of rehydrated shiitakes (0.5 oz dry) has 50 calories and 9g of carbohydrates… of which an amazing 6g is fiber! This same portion contains about 130 IU of vitamin D–or 30% more than a glass of fortified milk. Just to calibrate: 0.5 oz of sun-dried, sliced shiitakes is about 3/4 cups dry and rehydrates to about 1 cup “fresh,” ready-to-cook (or eat) shiitakes. Try substituting them for plain, button mushrooms in any recipe you have, or sauteing them in a smidge of olive oil with some garlic as a side dish. (A little bit of fat is needed to absorb the vitamin D). Alternatively, try this yummy recipe for Sesame Shiitake Noodles from Whole Foods. Use 1 cup dried shiitakes, rehydrated, instead of the 6 oz fresh that the recipe calls for, and try 100% buckwheat soba noodles instead of the capellini pasta if you want to make it gluten-free.

If you grind that dry 0.5 oz portion into powder (a mini coffee grinder works great here), it will produce about 1/2 cup of mushroom powder that you can blend into just about anything you can think of. As an experiment, we mixed 2 TBSP of the powder into 1 cup of warmed-up, store-bought organic chicken broth, waited 5 minutes, and tasted it. The result was really great: the mushrooms added a hint of flavor and a subtle amount of texture without overpowering the broth. Try keeping some ground sun-dried shiitakes in a tightly-sealed container in your pantry and get into the habit of adding it to soups, stews, grain dishes or sauces. It will add fiber and vitamin D to your food without affecting the flavor or texture dramatically.

Note that shiitakes should not be eaten raw, as sensitive individuals can develop a pretty severe rash from doing so. If you use the ground shiitake powder described above, be sure to incorporate it into soups, sauces or grains WHILE THEY ARE STILL COOKING to enable the mushrooms to be cooked as well!

[…] dried shiitake mushrooms (you can, of course, reconstitute them and still get the D. But its the drying process that activates the D, so fresh shiitakes will not contain the same levels. My calculations suggest that 1 cup of rehydrated shiitakes (0.5oz, or 3/4 cup, dry) contains about 130 IU of Vitamin D. […]

[…] vitamin D. Several online publications, however, report that naturally-dried shiitake mushrooms are excellent sources of this vital nutrient; these naughty-sounding fungi soak up UV rays faster than a Real Housewife of New Jersey at a […]